.bella-container {
  min-height: 100vh;
  background-color: #FAFCFF;
  font-family: 'Comic Sans MS', 'Marker Felt', 'Arial Rounded MT Bold', sans-serif;
}

/* 顶部渐变头部 */
.top-gradient {
  background: linear-gradient(135deg, #D4E9FC 0%, #B9DEF7 100%);
  padding: 24px 24px 40px;
  position: relative;
  overflow: hidden;
}

.header-content {
  position: relative;
  z-index: 10;
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  color: #1EB7D8;
  font-size: 18px;
  animation: floating 3s ease-in-out infinite;
}

.app-title {
  font-size: clamp(1.5rem, 5vw, 2.2rem);
  font-weight: bold;
  color: #1EB7D8;
  text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.1);
  margin: 0;
}

.user-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.8);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  overflow: hidden;
  animation: floating 3.2s ease-in-out infinite;
  animation-delay: 0.3s;
}

.welcome-message {
  background: rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  padding: 16px;
  display: inline-block;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  animation: floating 3.4s ease-in-out infinite;
  animation-delay: 0.6s;
}

.welcome-message p {
  margin: 0;
  color: #0A6E8A;
  font-size: clamp(0.875rem, 2.5vw, 1rem);
}

.welcome-message p:first-child {
  font-size: clamp(1rem, 3vw, 1.25rem);
  font-weight: 500;
  margin-bottom: 4px;
}

/* 浮动圆圈装饰 */
.floating-circle {
  position: absolute;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.circle-1 {
    position: absolute;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  width: 64px;
  height: 64px;
  background: #FFEB3B;
  right: -24px;
  top: 80px;
  animation: floating 3s ease-in-out infinite;
}

.circle-2 {
    position: absolute;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  width: 40px;
  height: 40px;
  background: #FFCDD2;
  left: 32px;
  bottom: 32px;
  animation: floating 3.2s ease-in-out infinite;
  animation-delay: 0.3s;
}

.circle-3 {
    position: absolute;
  border-radius: 50%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  width: 32px;
  height: 32px;
  background: #C8E6C9;
  right: 33.333%;
  top: 40px;
  animation: floating 3.4s ease-in-out infinite;
  animation-delay: 0.6s;
}

/* 主要内容区域 */
.main-content {
  padding: 0 20px 80px;
  margin-top: -16px;
}

.feature-card {
  border-radius: 24px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
  border: 2px solid #D4E9FC;
  padding: 24px;
  transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  position: relative;
  overflow: hidden;
}

.feature-card:active {
  transform: scale(0.95);
}

.card-icon {
  width: 64px;
  height: 64px;
  background: #D4E9FC;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #1EB7D8;
  font-size: 24px;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.5rem;
  font-weight: bold;
  color: #374151;
  margin: 0 0 8px 0;
}

.feature-card p {
  font-size: 0.875rem;
  color: #6B7280;
  margin: 0;
}

.card-arrow {
  width: 45px;
  height: 45px;
  background: rgba(30, 183, 216, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #1EB7D8;
  font-size: 20px;
  position: absolute;
  bottom: 34px;
  right: 24px;
}

/* 角色展示 */
.character-container {
  display: flex;
  justify-content: center;
  margin: 32px 0;
}

.character {
  position: relative;
  width: 112px;
  height: 112px;
}

.character img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
}

.character-badge {
  position: absolute;
  bottom: -8px;
  right: -8px;
  width: 40px;
  height: 40px;
  background: #1EB7D8;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  animation: floating 3s ease-in-out infinite;
}

/* 教材选择模态框 */
.textbook-modal {
  border-radius: 24px;
  overflow: hidden;
}

.modal-header {
  text-align: center;
  margin-bottom: 20px;
}

.modal-header h3 {
  color: #1EB7D8;
  font-size: 1.25rem;
  font-weight: bold;
  margin: 0 0 4px 0;
}

.modal-header p {
  color: #6B7280;
  font-size: 0.875rem;
  margin: 0;
}

.textbook-item {
  background: white;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  border: 2px solid;
  position: relative;
  transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.textbook-item:active {
  transform: scale(0.95);
}

.textbook-item.selected {
  border-width: 3px;
}

.book-ribbon {
  position: absolute;
  top: -5px;
  right: -5px;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  color: white;
  font-weight: bold;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  z-index: 1;
}

.ribbon-kb1 { background: #FF9E7D; }
.ribbon-kb2 { background: #8CD790; }
.ribbon-kb3 { background: #FFD966; }
.ribbon-kb4 { background: #A7ACEF; }

.book-corner {
  position: absolute;
  bottom: 0;
  right: 0;
  width: 20px;
  height: 20px;
  background: linear-gradient(135deg, transparent 50%, rgba(255, 255, 255, 0.6) 50%);
}

.textbook-info {
  padding: 12px;
}

.textbook-info h4 {
  font-size: 0.875rem;
  font-weight: bold;
  color: #374151;
  margin: 0 0 4px 0;
}

.textbook-info p {
  font-size: 0.75rem;
  color: #6B7280;
  margin: 0;
}

.selected-indicator {
  position: absolute;
  bottom: -5px;
  right: -5px;
  width: 20px;
  height: 20px;
  background-color: #1EB7D8;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 12px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* 提示弹窗 */
.alert-modal {
  border-radius: 24px;
  overflow: hidden;
}

.alert-content {
  border-radius: 24px;
  overflow: hidden;
  text-align: center;
  padding: 16px 0;
}

.alert-icon {
  width: 64px;
  height: 64px;
  background: #D4E9FC;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #1EB7D8;
  font-size: 24px;
  margin: 0 auto 16px;
}

.alert-content h3 {
  font-size: 1.25rem;
  font-weight: bold;
  color: #374151;
  margin: 0 0 8px 0;
}

.alert-content p {
  color: #6B7280;
  margin: 0;
}

/* 动画 */
@keyframes floating {
  0% { transform: translateY(0px); }
  50% { transform: translateY(-12px); }
  100% { transform: translateY(0px); }
}

.floating {
  animation: floating 3s ease-in-out infinite;
}

.floating-delay-1 {
  animation: floating 3.2s ease-in-out infinite;
  animation-delay: 0.3s;
}

.floating-delay-2 {
  animation: floating 3.4s ease-in-out infinite;
  animation-delay: 0.6s;
}

.popup-animation {
  animation: popup 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes popup {
  0% { transform: scale(0.8); opacity: 0; }
  70% { transform: scale(1.05); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}